Broaching machine



F. J. LAPOINTE BROACHING MACHINE Filed Sept-6, 1928 Aug. 30, 1932.

2 Sheets-Sheet l F. J. LAPOINTE BROACHIN'G MACHINE Fil d Sept. 6, i928 Iz- U l l l III l l Patented Aug. 30, 1932 FRANCIS J. LAPOIN'IE, ANN ARBOR, MICHIGAN BROACHING MACHINE Application and September 6. 1923. Serial No. 304,247.

My invention has for its object to produce a breaching machine whereinthe draw or the punch is produced hydraulically bypressure over a relatively large area, while the return I is produced by pressure over a small area with consequent quick return between broaching operations. In the preferred form of constructions embodying my invention, a fixed piston and a movable cylinder are used, having two pressure areas of different sizes. The piston supporting member extends through one end of the cylinder which reduces the volume within and .of the pressure area on the end of the cylinder on that side of the piston, while the otherend of the cylinder has the full effective area of the interior of its cross section. The first produces a magnified movement to produce a rapid change of one dimension of the volume of oil introduced into the cylinder which produces a quick stroke of the cylinder upon the introduction of a small quantity of oil, and the second produces a powerful broaching stroke. Thus, by my invention, liquid of substantially uniform pressure per square inch may be used and yet produce a powerful working stroke and a quick return stroke. u The invention alsohas for its object to provide a hydraulic pressure means at a point above the face plate used for retaining the object while being broached, which produces a draft as between the actuating pressure and the point of resistance to the movement induced by thatpressurm'and eliminates or reduces the variable deformation occurring by reason of the elasticity of interconnected parts where the actuating pressure point is located below the face plate. The invention also eliminates a large part of the exteriorly located piping through which the transmission liquid is transposed and thus the machinenot only presents an attractiveappearance, but also, its parts are economically used to perform double functions which materially reduces the number of parts and at the same time in creases its efficiency.

The invention may be contained in broaching machines that vary in their details, and to illustrate a practical application of the invention,'I have selected a vertical broaching machine containing the invention as an example of such structures, and shall describe it hereinafter. The broaching machineselected is shown in the accompanying drawings. L Fig. 1 illustrates a front view of the broachof the machine. Fig. 3 illustratesa top view of the machine. Fig. 4 illustrates a rear view of the base of the machine. Fig. 5 illustrates a view of a section taken on the plane of the line 55 indicated in Fig. 21 Fig. 6 illustrates a View of a section taken on the plane of the line 66 indicated in Fig. 5. Fig. 7

illustrates a view of a. section taken on the plane of the line 7-7 indicated in Fig. 3.

Fig. 8 illustrates a view looking upwards from beneath the base of the machine.

The machine is provided with a base 1 on which the parts of the niachine are mounted. It has a frame that is composed of three vertical standards or rods 2 and 3. The standards 2 are secured to blocks 4 that are bolted to the base 1, while the standard 3 is secured to the base by a suitable nut 5. The upright standards 2 and 3 areconnected together by a suitable triangular frame 7 which, together with the standards, operates to increase the rigidity of thesuperst-ructure of the machine.

The standards 2 also form guides for the crosshead 8 that is adapted to slidably move along the standards. They also form a support for the face plate 9. The face plate 9 is provided with openings through which the standards 2 extend. It is secured in position by means of a pair of split collars 10 that may be located in channels 11 formed in the standards 2 and also in recesses 12 formed in the upper surface of the face plate 9 where the standards 2 pass through the face plate 9. The face plate 9 may also be further secured in position by means of the key bolts 13. Thus there is produced a means for securely locking the face plate 9 inposition as against the pressure that it is subjected to by the machine during the broaching operations. If it is desired to adjust the face plate 9, relative to the other parts of the machine, it may be done by forming a plurality of channels 11 in order to provide for securing the face mg machine. Fig. 2 illustrates a side view plate 9 at different positions along the standards 2, depending on the stroke or initial osgaion that it is desired to give the crossea W The crosshead 8 slidably moves along the standard 2 above the face plate 9 and is operated by a pair of cylinders v that are connectedto theouter ends of the crosshead 8. A tool chuck or head 21 projects downward W from the crosshead 8 towards the top of the face plate 9. It may be provided with the usual key slot 22 into which a key may be inserted for locking thebroaches to the crosshead 8. The work is supported on the under side of the face plate 9 and the broach extends through a suitable opening formed in the face plate 9, in the manner well known in the art. Thus, the upper ends of the cylinders 20, which are sub ected to hydraulic pressure, are located well above the face plate 9.

The c linders 20 are provided with cylinder heads 23 that may be threaded into the upper ends of the cylinders 20. They are. provided with threaded hubs 24 that extend through the crosshead 8, and are secured to the crosshead by means of the nuts 25. Sta tionary pistons 26' are located within the cylinders 20 and are provided with the usual M sealing piston rings 27. The pistons 26 are supported in position by means of hollow cylindrical stems or members 28' that protrude throu h the lower ends of the cylinders. Suita le glands or packing rings 29 65 close the spaces formed between the walls of the members 28 and the cylinders 20. There is thus formed large pressure areas for the actuation of the cylinders 20 at their upper ends, namely, on the inner surface of the cylinder heads 23, and also a very much smaller volume per unit of length of the cylinders in their lower parts, namely, within the annular chamber located intermediate the cylindrical surface of the members 28 and the inner surfaces of the cylinders 20. This gives a powerful upward stroke of the cylinders and of the crosshead during the broaching operation and a very quick return, since the volume changes but a small amount per unit of length of stroke of the cylinder.

The pistons 26 are connected to the blocks 4. The hollow piston supporting members 28 extend through the blocks 4 and are secured by nuts 35 that are threaded onto the ends of the hollow cylindrical members 28. A pair of pipes 36 and 37 extend through the cylindrical piston supporting members 28 to the pistons 26. The pipes 36 are connected through bores 38 to points above the istons, while the pipes 37 are connected t rough bores 39 to points below the pistons. Thus liquid conveyed. through the pipes 36 are didected into the upper ends of the cylinders and the pressure that it is subjected to is transmitted throughout the areas of the cylinbers 28.

der heads 23. This is during the working stroke of the machine. During the return stroke of the, machine, the liquid is transmitted through the pipes 37 and into the annular chambers formed between the cylindrical members 28 and the cylinders 20. By reason of the difi'erentrates of change in volume of the liquid thus transferred in these two strokes, the pipes 37 may be made much smaller than the pipes 36 which enables the use of much smaller pipes 37 and, consequently, much larger pipes 36 within the confines of the cross sectional area of the interior of the cylindrical piston supporting memother o the pipes is being used to exhaust the cylinder to which it is connected.

The pipes 36 are connected together and the pipes 37 are connected together and, by suitable Ts and elbows, the pipes are connected to the four-way valve 45 having a liquid inlet 46 and a liquid outlet 47 which may be connected, respectively, to the outlet an intake of a suitable pump, or other source of supply of liquid under pressure, in the manner well known in the art.

The operations of the machine are thus controlled by manipulation of the valve 45. In the form of construction shown, the valve 45 may be operated manually to start the broaching operation and then automatically upon the completion of the broachingstroke and again automatically to stop the machine. The valve 45 ma be controlled by two levers, such as the da lever 50 and the hand lever 51. The pe al lever 50 is pivotally supported in a air of ears 52 and a boss 53 that project rom the walls of the base 1 of the machine. The pedal lever 50 is provided with two arms 54 and 55. The arm 54 is connected by a link 56 to the hand lever 51 and, consequently, the hand lever 51 is moved with the pedal lever 50 and also the pedal lever 50 is moved when the hand lever 51 is operated. The arm 55 of the pedal lever 50 is connected to the valve 45 by means of the link 57 and so that when the pedal lever 50 is depressed, the valve 45 is rotated so as to connect the pipe 36 with the inlet pipe 46 and the pipe 37 with the ipe 47 which is the outlet p1pe of the mac ine. This produces a pressure on the cylinder heads 23 which raises the crosshead I 8. A rod 58 is connected to the crosshead 8. 1 5 It extends through a slot formedin the hand lever 51. If desired, the hand lever 51 may be made in the form of a Y and the end of the rod 56 may be located within the arms of the Y and the rod 58 may extend between the ISO Pas arms of the Y and ass throu lithe hand lever 51. The rod 58 isprovide with a pair of duced by the stop 59, thepedal lever 50 is raised by the movement of the link 56. The

under 37 while at the same time the outlet pipe 47 is connected with the pipe 36. The pressure lever 50 operates the valve to establish connection between the source of supply of liquid pressure through the pipe 46 to the pipe of the liquid is thus communicated to the i 1. In Ca vertical broaching a f combination of a face plate 0 lower end ofthe cylinder 20, while the upper end of the cylinder is exhaustedland thecrosshead 8 descends. This may continue its downward movement until the upper stop 59 operates on the lever51 and the pedal to locate the valve 45 in a closed position. If

a desired, however, the valve 45 may again be andshells connected to the istonsand secured in the base, the pistons avingpassageways communicatingwith opposite sides of the pistons for conducting a uid tothe cylinders on opposite sides 0 the pistons.

In witness whereof I have hereunto signed my name to thisspecification. FRANCIS J. LAPOINTE.

operated to cause the machin t Perform its broachin strokeu ,1 a

Thus, ,have lrovided an exceedingly efficient breaching machine havin relatively few parts andone whichmay e rendered automatic as wellwas one that is subject to constant manualgcontrol, and one which has v afpowerfulbroaching stroke and a quick re- Iclaim: I i

machine, the r maintaining 3 the workin position, a reci rocable crossconnectin a broachin tool to the cro'sshead,

on each side tonslocated in the cylinders the top of the pistonslocated above the face plate, a pair l head locatedabove the face p ate, means for n a base beow the wor plate c linder heads connected tothe said crosshea j of the broach connecting means, cylinders,

connected to the said cylinder heads, pisof piston sleeves attached to saidbase for supporting the said pistons eachvof the pistons aving passageways therethrough, one connecting the exterior of the sleeve at a point onone side of the piston, the other connecting at apoint intermediate the iston and the said cylinder head, the cylin ers having walls surrounding the said sleeves.

2. In a broaching machine, a base, aiwork plate, a pair of vertically extending rods secured in the base and tothe work plate and above the work plate, a cross ead secured to the upper end of the said roads, a drawhead located intermediate the work plate and the crosshead and guided in its movements by therods, apair of c linders connected to the drawhead, pistons ocated in the cylinders extending through the work late to a point Ill) 

